Environmental and financial assessment of phosphorus loss from food waste in the academic institutions

BACKGROUND AND OBJECTIVES: Food waste is a global issue as it has an environmental impact by releasing large amounts of carbon dioxide equivalent throughout their biodegradation. Academic institutions are significant sources of food waste, as students spend over 15 years of their lives living and learning in these environments. Considering the intake of two to three meals daily, a significant quantity of food waste may be produced. Regrettably, a significant amount of food waste usually finds its way to landfills; as a result, the valuable phosphorus it held is lost during disposal. The study objectives were to investigate the practical management of food waste in the academic institutions, especially in the part related to phosphorus recovery.METHODS: Three academic institutions in Bangkok area were chosen, i.e. a primary school, a technological college, and a public university. For three consecutive days, sampling was performed at each institution, followed by an analysis of physical and chemical characteristics in the laboratory.FINDING: The study indicated that the quantity of food waste generated by three institutions varied between 20 and 206 kilograms on a daily basis. In comparison to their total solid waste (41–229 kilograms per day), food waste accounted for 40–90 percent of the total waste generated by three academic institutions. This study categorized food waste into two distinct types: uncooked food waste and cooked food waste. The phosphorus content of uncooked food waste ranged from 0.09 to 0.29 milligrams phosphorus per gram, whereas those of cooked food waste ranged from 0.53 to 0.76 milligrams phosphorus per gram. From mass balance calculation, the total phosphorus mass entering the waste management system possibly ranged from 7.9 to 141.3 grams’ phosphorus per day, while phosphorus loss ranged from 2.3 to 13.5 grams per day. According to the composting scenario analyzed in this study, the projected yield of fertilizer-like products varied from 0.3 to 19 tons annually. The utilization of food waste could reduce waste collection and disposal costs by up to 1,395–1,870 United States Dollar per year. Furthermore, extracting phosphorus from food waste may contribute to mitigating the challenge posed by restricted global phosphorus reserves.CONCLUSION: This analysis firmly suggests for the segregation of food waste to improve the evaluation of phosphorus flow and recovery. It is vital to prioritize phosphorus recovery for agricultural purposes.